This invention relates to a novel drill bit for drilling in wood and similar materials.
Conventional wood bits are so designed that, apart from the small screw at the end thereof for engaging the bit with the work, the drill bit immediately begins the drilling of a hole of the full desired diameter. This requires a very substantial pressure to be exerted manually by the user. A further problem is encountered when it is desired to drill a larger hole where a smaller hole already exists so that the small feed screw at the end of the conventional wood bit is ineffective in feeding the drill into the work. A still further problem exists in cases where the wood bit is apt to encounter nails, metal lathing, plaster or other material which harmfully affects the usual knife edge portions provided at the tip end of conventional wood bits.
My prior U.S. Pat. No. 3,758,222 dated Sept. 11, 1973 shows a conical drill bit which is designed to produce holes of various sizes in relatively thin sheets, usually metal sheets. The bit of the present invention is for a substantially different purpose but bears some physical resemblance to the bit of my prior patent in its generally stepped conical form.